Elevation of surfactant protein A in plasma and sputum in cigarette smokers

Abstract

Serum surfactant protein (SP)-A has been postulated to associate with pulmonary fibrosis, but its role in cigarette smoking-related lung diseases is undefined.SP-A levels in plasma and induced sputum in nonsmokers, smokers with respiratory symptoms (cough and/or phlegm) and symptom-free smokers were assessed using a validated EIA method. A total of 474 current smokers without any diseases or medications were enrolled and followed for 2 yrs with 111 of them succeeding in stopping.Plasma SP-A level was detectable in all subjects and elevated in smokers independently of the symptoms compared to nonsmokers (p50.001). After 2 yrs of follow-up, the SP-A level was higher in those who continued smoking compared to the quitters (p,0.001). Plasma SP-A levels were associated with age, smoking history and lung function. Sputum (n5109) SP-A was nondetectable in most nonsmokers, whereas smoking and symptoms increased sputum SP-A highly significantly (p50.001).In conclusion, SP-A may be involved in pathogenesis of cigarette smoking-related lung diseases. Further studies are needed to elucidate the role of SP-A in chronic obstructive pulmonary disease.

Serum levels of surfactant proteins in patients with combined pulmonary fibrosis and emphysema (CPFE)

“…This is in accordance to previous studies showing that smokers had decreased levels of SP-A and SP-D in the bronchoalveolar lavage (BAL) fluid [52] although they seemed to express higher circulating levels of the former [53]. A possible explanation of these findings was that smokers may present an alveolo-capillary leakage of surfactant proteins into the blood [54].…”

Elevated sputum BPIFB1 levels in smokers with chronic obstructive pulmonary disease: a longitudinal study

“…The participants were part of a longitudinal study, of a cohort of smokers and nonsmokers, being conducted in northern Finland. The details of the project and the inclusion and exclusion criteria have been previously published (16,20,34,35). In brief, the exclusion criteria consisted of chronic pulmonary or other diseases requiring regular medication, allergies, and risk factors for other pulmonary diseases, e.g., known exposures, bronchiectasis, malignancies, and also previous lung tuberculosis.…”

“…In recent proteomic studies from our laboratory the major findings included an elevation of surfactant protein-A (SP-A) and a decrease of specific variants of the receptor for advanced glycation end products (RAGE) in lung tissue (25,26) and polymeric immunoglobulin receptor in sputum samples from patients with COPD (24). Of these, SP-A and soluble RAGE have been validated in longitudinal approaches in larger cohorts (16,20). Our previous proteomics study also identified elevated levels of bactericidal/permeability-increasing protein fold containing protein B1 (BPIFB1, formerly known as LPLUNC1) in induced sputum from smokers and patients with COPD compared with nonsmokers (24).…”

Surfactant protein A is decreased in the lung of rats with hepatopulmonary syndrome

“…The presence of SP-A in serum was reported in pulmonary fibrosis 24 . In fact, the present study found surfactant protein A (SP-A) in the blood in all groups of animals.…”